Lee, Total Eclipse of the Heart
[Apologies for those unfamiliar with music theory. There’s really no other way to explain the genius of this without resorting to a lot of roman numerals.]
This song has dozens of key changes, but I’m focusing on the epic transition from the verse to the chorus: E major to A flat major.
The chord progression through the first verse is a little unconventional, but with each “turn around,” nothing feels too jarring. That’s because the song moves through its key changes using somewhat conventional methods: the flat VII chord functions as the dominant of the upcoming key, so each new key has a harmonic relationship with the previous key.
All fine and dandy until the verse transitions to the chorus. The preparation for the key change (the last line of the verse: “Turn around, bright eyes”) uses a conventional chord progression: E to A major 7, or I to IV. So far so good. But then comes the transition to the chorus: “Every now and then I fall a-PART.” WHAM! The song transition from E major to A flat major in the most unusual way: from an A major seventh chord, the IV (subdominant) of the previous progression, to A flat major chord, the I (tonic) chord, of the new key.
What’s amazing about this key change is that the connecting chords are just a half step away from each other, and the preparatory chord isn’t the I of the previous key (the cheeseball way of putting two chords one half step apart from each other and modulating). Better still, the connecting note between Amaj7 and A flat major is the major seventh of the first chord, a dissonant interval between the root and the melody, which then becomes the tonic note of the new key. In other words, WHAM! The dissonant note is now the tonic!
I could go on about a number of amazing things about this song: the dynamic range of the melody line (four steps above an octave) and the contrast between the funky-modal verse and the super conventional I-vi-IV-V chorus, but let me leave you with this. Take a look at the transcription:
Notice that the key of four sharps transform into the key of four flats.
A Total Eclipse of the Key Change if there ever was one.